Scaffold straightening method and apparatus

ABSTRACT

METHOD AND APPARATUS FOR USE IN THE REFURBISHING OF ELONGATE SCAFFOLDING TOWER SECTIONS WITH HAVE BECOME BENT DUE TO ROUGH HANDLING. SAID TOWER SECTIONS ARE OF THE TYPE HAVING A GENERALLY TRIANGULAR CONGIGURATION IN SECTION AND FORMED OF A PAIR OF ELONGATE BASE FRAME MEMBERS AND AN ELONGATE APEX FRAME MEMBER, WHICH FRAME MEMBERS ARE JOINED EACH TO THE OTHER BY A PLURALITY OF CROSS-BRACES. SAID APPARATUS INCLUDES A FRAME HAVING AN ELONGATE BED PORTION FOR SUPPORTING A TOWER SECTION TO BE STRAINGTENED AND FIRST AND SECOND DIE MEANS OPERABLY ASSOCIATED WITH SAID BED PORTION ENGAGING THE RESPECTIVE FRAME MEMBERS SUCH THAT STRAIGHTENING FORCES MAY BE APPLIED TO THE BENT PORTIONS THEREOF. IN ADDITION, THIS APPARATUS ALSO INCLUDES MEANS FOR APPLYING AN AXIAL LOAD TO THE TOWER SECTION SUCH THAT THE RESPECTIVE FRAME MEMBERS MAY BE PLACED IN TENSION DURING THE APPLICATION OF STRIGHTENING FORCES THERETO BY SAID DIE MEANS.

NOV. 30, 1971 v HANSEN ETAL 3,623,350

SCAFFOLD STRAIGHTENING METHOD AND APPARATUS Filed Feb. 2, 1970 5 Sheets- Sheet l UlUJ NOV. 30, 1971 HANSEN ETAL 3,623,350

SCAFFOLD STRAIGHTENING METHOD AND APPARATUS Filed Feb. 2, 1970 3 Sheets-Sheet IA/ VS/V TO F5 Nov. 30, 1971 iiili' Mini R. N. HANSEN ET AL 3,623,350

SCAFFOLD STRAIGHTENING METHOD AND APPARATUS Filed Feb. 2, 1970 3 Sheets-Sheet 5 1- m we! Jl/ j/amew United States Patent O 3,623,350 SCAFFOLD STRAEGHTENXNG METHOD AND APPARATUS Robert N. Hansen, 616 Wilson Road, Lombard, Ill.

60148; George T. Hempel, Rte. 1, Box 48A, Bartlett,

Ill. 60103; and Raymond Noesges, 3521 Louis St.,

Franklin Park, ill. 60131 Filed Feb. 2, 1970, Ser. No. 7,552 Int. Cl. B2ld 3/10 U.S. Cl. 72-362 33 Claims ABSTRACT OF THE DISCLOSURE Method and apparatus for use in the refurbishing of elongate scaffolding tower sections which have become bent due to rough handling. Said tower sections are of the type having a generally triangular configuration in section and formed of a pair of elongate base frame members and an elongate apex frame member, which frame members are joined each to the other by a plurality of cross-braces. Said apparatus includes a frame having an elongate bed portion for supporting a tower section to be straightened and first and second die means operably associated with said bed portion engaging the respective frame members such that straightening forces may be applied to the bent portions thereof. In addition, this apparatus also includes means for applying an axial load to the tower section such that the respective frame members may be placed in tension during the application of straightening forces thereto by said die means.

BACKGROUND OF THE INVENTION The present invention pertains to a method, and apparatus for practicing said method, usable in the reconditioning of bent or distorted tower sections. More particularly, said method and apparatus are primarily for use in the straightening of tower sections used in the fabrication of scaffolding, as will be detailed more completely hereinafter.

The particular form of scaffolding to which the present invention relates is of a type used by masonry contractors. Generally, this scaffolding employs a plurality of interconnected, vertical towers which are aligned in a plane, substantially parallel to that of a proposed masonry wall of a building under construction. Each tower has a carriage member slidably mounted thereon for controlled vertical movement. Once the towers, with their respective carriages, are in position, planking is laid from one carriage to the other to bridge the distances between the respective carriages, thereby providing a platform upon which the masons and laborers work. Due to the slidable mounting of the carriages on the respective towers, this platform can be raised or lowered as desired, and additional tower sections added as the height of the wall increases.

Wide acceptance has been accorded this type of scaffolding by masonry contractors due to the numerous advantages and conveniences afforded thereby. For example, but to name a few, once initially set up only minimal assembly time is needed to raise the scaffolding to the final height required; increased productivity for the masons is realized due to a minimization of down time and the fact that they can work waist high at all times their optimum production level; and previously assembled scaffolding may be moved from one wall to another substantially intact.

The respective towers mentioned above are, in fact, assemblies made up of a plurality of interconnected, stacked tower sections, each of which may be up to 9 feet in length. Each section is of a generally triangular configuration, being comprised of a pair of base frame elements and an apex frame element with cross-braces joining the respective frame elements. The ends of a tower section are such that they effectively define male and female connector portions. More specifically, the end of a section which is to function as a female portion is of a standard open ended construction, while at the opposite end, the various frame elements are slightly undersized so that this end portion can be received within the female end portion of an adjacent section.

While contractors have found this scaffolding arrangement extremely effective and desirable, a recurring problem has plagued them. That is, these tower sections are susceptible to damage and soon become unserviceable requiring the purchase of a replacement section, since the cost of reconditioning, prior to the present invention was prohibitive. Underlying this, is the existence in many states of laws, which are termed scaffolding statutes that impose strict liability on a contractor when his scaffolding fails. Accordingly, contractors are quick to retire those tower sections which have become bent or distorted.

The above-mentioned damage to the tower sections may occur in many ways, for example, in transportation or during the assembling and disassembling of the scaffold. During rough handling, the respective frame ele ments are subjected to impacts which may result in the frame elements becoming bent which also often result in a bulging or distorting of the adjacent cross-braces. While several such bends may not render a section unserviceable, over a period of time, a tower section will become bent and distorted at a multitude of locations along its length, the cumulative effect thereof resulting in an unserviceable section. Therefore, contractors using this type of scaffold have discovered an ever increasing stockpile of scrap sections, each of which must be replaced.

Prior to the present invention, the only manner of reconstituting damaged sections was to straighten individually each bend in the frame elements or the cross-braces, and in many instances complete replacement of said braces. This straightening operation was primarily a manual one with a worker employing various tools such as torches, clamps, pry bars, hydraulic pistons, and the like, in applying the straightening forces to the bent portions of the section. Eventually, the section could be straightened sufficiently to render it safe for use; however, the labor cost involved normally exceeded that of a new section, therefore making straightening economically impractical.

SUMMARY OF THE INVENTION The apparatus, and the method of use of said apparatus, of the present invention provide means for the straightening of damaged scaffolding tower sections in a manner sufficient to overcome the disadvantages of the prior art methods, while providing numerous other advantages as will be apparent from the detailed description of the invention to be evolved hereinafter. These advantages are provided by the employment of apparatus comprising: a frame having a bed portion upon which the base frame members of a tower section rest in supported engagement; first die means including an elongate shoulder disposed adjacent an edge of said bed portion, and elongate ram means operably disposed relative to said bed portion on a side opposite said first shoulder means and thereby defining a second shoulder means, said ram means being reciprocal to provide for relative movement between said first and second shoulder means which movement is employed in establishing straightening forces in said base frame members and the interconnecting cross-braces; and second die means for engaging the apex frame member of said tower section to establish straightening forces in said apex frame member and the cross-braces joining said apex member to the base frame members.

3 DESCRIPTION or THE DRAWINGS A better understanding of the present invention, its organization and operation may be had by reference to the following detailed description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view of a tower section of the general type to be straightened by the present invention;

FIG. 2 is a perspective view of a preferred embodiment of the apparatus of the present invention empolyed in straightening a tower section such as shown in FIG. 1;

FIG. 3 is an end elevational view of the apparatus of FIG. 2 with a tower section positioned thereon and the apparatus in position for applying straightening forces to the base frame elements;

FIG. 4 is an end view similar to FIG. 3 and illustrating the manner in which straightening forces are applied to the apex element;

FIG. 5 is a top plan view of the apparatus of FIGS. 24, with the carriage portion of the second die means removed;

FIG. 6 is a fragmentary perspective view of the supporting bed of the present apparatus, with a segment thereof broken away to illustrate a preferred form of the lower die assembly of the second die means used in straightening the apex frame elements;

FIG. 7 is a sectional view taken along the line 7-7 of FIG. 5, in the direction indicated;

FIG. 8 is a schematic view illustrating a manner of applying straightening forces to outwardly protruding bends in the base frame eleemnts; and

FIGS. 9 and 10 are schematic views illustrating a manner of applying straightening forces to inwardly extending bends in the base frame elements, as an alternate to that shown in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in more detail wherein several embodiments or variations of the present invention are shown, with like reference characters being used throughout, FIG. 1 illustrates a tower scaffolding section of the type under discussion, and designated generally 20. The tower section 20 is fabricated from three elongate frame elements 22, 24 and 26 which are in the shape of an angle-iron, with each being interconnected to the other by a plurality of cross-braces 28. As can be seen, the tower section 20 is generally of a configuration resembling an isosceles triangle such that the cross-braces 28 interconnecting frame elements 24 and 26 define a base portion, while the cross-braces 28 joining frame element 22 to elements 24 and 26 define leg portions meeting at apex frame element 22. Accordingly, for purposes of description, the elements 24 and 26 are designated base frame elements, and the frame element 22 is designated an apex frame element.

The tower section 20 also includes male and female type connector means defined by the respective end portions thereof, wherein the portion 20' provides a female connector and the portion 20 the male connector, such that a plurality of these sections may be interconnected to form a tower. The male end portion 20" is defined by three relatively short frame sections 22, 24 and 26 which are smaller in size than the corresponding frame elements 22, 24 and 26 so as to adapt this end portion 20" for insertion in a female end portion 20 of an adjacent tower section.

Knowledge of the manner in which tower section 20 became damaged, and the various types of damages that may result, is believed necessary in understanding of this invention, and these will be discussed briefly as a prelude to the detailed description of the apparatus and method of said invention. That is to say, that during transportation, assembly and disassembly of the scaffold components, which include tower section 20, extremely rough handling ensues. Accordingly, these sections 20 are subjected to repeated and numerous impacts, each of which may result in one or the other of the frame elements 22, 24 or 26 being bent or otherwise distorted. It can be appreciated that due to the triangular configuration of section 20, it is these elements 22, 24 and 26, rather than the cross-braces 28 which normally bear the brunt of this mishandling. On the other hand, the ends of the crossbraces 28 are rigidly connected to said frame elements by welding, such that deformation of a frame element may result in a corresponding buckling or distortion of a cross-brace connected to said element in the vicinity of said deformation.

Normally, the bend or irregularities occurring in the frame elements 22, 24 and 26 will be of a type which extend or bulge inwardly of the tower section; however, outwardly protruding distortions are frequently encountered.

With the foregoing in mind, attention is now invited to FIGS. 2-10, wherein a preferred embodiment of the apparatus or straightening press of the present invention is shown, and designated generally 30. Considering the numerous forms or variations of bends that may occur, as well as the differences in the severity of each, it should be apparent that the apparatus 30 must be adapted to accommodate a Wide variety of situations. And further, that in straightening an individual section, not all of the straightening procedures and elements of said apparatus 30 need be employed, but only those sufiicient to render a particular tower section serviceable.

The general or overall construction of the apparatus or press 30 will now be discussed with specific reference to FIGS. 2 and 3. Said apparatus 30 is comprised of a frame 32 having supporting legs '34 and an elongate bed portion 36 upon which a tower section 20 is adapted to rest. Operably associated with the bed 36, are first and second die means or assemblies 38 and 40, respectively, which, as will be detailed more fully hereinafter, are capable of establishing straightening forces in the frame elements 22, 24 and 26, as well as the cross-braces 28. In addition, directing attention to the right-hand portion of FIG. 2, as viewed, the preferred illustrated embodiment may also include a reciprocally mounted member 42 that may be employed to correct axial misalignment in the male and female end portions 20 and 20", as well as to place an axial load on the entire tower section 20 during the application of straightening forces thereto by the first and second die means 38 and 40.

The member 42 is carried by a connector rod 44 which is associated with a double acting fluid cylinder (not shown) such that reciprocal movement of said member may be effected as indicated by arrow 43. The reciprocal member 42 is shaped to conform to the interior configuration of the tower section 20 such that it can be forcibly disposed within an end portion thereof to bias this portion back of the axial alignment. In addition, once the member 42 is disposed within an open end of a section 20, the opposite end thereof may be fixed, as illustrated in FIG. 5, and a pin 46 or some other means employed effectively to connect said member 42 to the tower section 20. After this connection is accomplished, the member 42 is retracted to place an axial load on said section '20, placing the respective frame elements 22, 24 and 26 in tension.

The apparatus or press 30 is designed for operation with the base elements 24 and 26 resting on the bed 36 as shown in FIG. 3. Accordingly, with a tower section 20 so positioned, the first die means or assembly 38 is employed to apply straightening forces to said base elements, as discussed immediately hereinafter.

The first die assembly 38 is comprised primarily of an elongate shoulder 50, formed integral with frame 34 and adjacent bed 36, so as to extend the entire length thereof such that one of the base frame elements 24 or 26 may be butted thereagainst. Opposing the shoulder 50, and positioned relative to the bed 36 for engagement with the other base frame element is a ram assembly 52. This assembly 52 includes a movable ram 54 defining a shoulder 55 complementary to shoulder 50, and a plurality of double-acting fluid operated pistons 56 operably connected to the ram 54 by piston rods 57 for effecting reciprocal movement of said ram. The ram assembly 52 is carried on a portion 58 of the frame 36, which is in fact, an extension of bed 36.

The shoulder 50 and the ram assembly 52 comprise the primary elements of the first die means 38, and as will be apparent from the discussion to follow, these elements alone may be employed in the straightening of certain types of bends in the base elements 24 and 26. However, the first die means 38 also include various accessories or implements which are employed in straightening bends that cannot be accommodated by the shoulder 50 and the ram assembly 52 alone. Irrespective of the type of bend in the base elements 24 and 26 to be straightened, however, the relative movement attainable with the aforementioned ram arrangement 52 is employed in the straightening procedures for the base elements 24 and 26.

Assuming then that either or both of the base elements 24 or 26 have been damaged in such a manner as to produce outwardly extending distortions, attention is now directed to the schematic illustration of FIG. 8, wherein said distortions are designated A. In this instance, a damaged tower section 20 is placed on the bed 36 and the ram assembly 52 is operated to advance the ram 54 inwardly toward shoulder 50 until said shoulder 50 and the shoulder 55 on ram 54 engage the distorted portions A. Accordingly, continued movement in the direction indicated by the arrows 60 forces portions A inwardly of tower section 20 into alignment with the unbent segments of the respective base elements 24 and 26.

Another type of deformation or distortion occurring in the base elements 24 and 26 is that wherein the bends extend inwardly of the tower section. For reference purposes, this type of distortion is designated B in the drawings and is probably the most common encountered. In the illustrated embodiment of the present invention, two sets of accessories useable with the shoulder 50 and the ram assembly 52 for straightening this type of bend are shown. Accordingly, it is the shoulder 50, the ram assembly 52, and one or both of these accessories which comprise the first die means 38.

More particularly, the first of these forms of accessories and the manner of application are illustrated in FIGS. 3, and 7, While FIGS. 9 and illustrate schematically the construction of the second form and its manner of use. The straightening procedures eifected with the respective accessories differ primarily in that with the first relative separating movement between the shoulders and is employed, while the second utilizes relative movement of said shoulder toward each other. However, it should be noted that accessories and the straightening procedures effected therewith are not mutually exclusive, and if desired or needed, both may be employed in the straightening of an individual tower section, or neither, if no bends of the type B are encountered.

With regard to the first of these accessories, illustrated in FIGS. 3, 5 and 7, a plurality of first and second clamping members 62 and 64 are provided which are carried by the shoulder 50 and the ram 54, respectively. The clamp members 62 are engaged with the base elements 26 at selected locations along the length thereof including any inwardly bent portions B so as to maintain the base element 26 substantially stationary with regard to shoulder 50, note FIGS. 3 and 5. The clamping members 64, carried by ram 54, are engaged only with inwardly bent portions B of the base element 24, as illustrated in FIGS. 5 and 7. Next, the ram 54 is moved in a direction away from shoulder 50 as indicated by the arrow 65 in FIG. 7. Since the tower section 20 remains stationary by virtue of the clamped engagement of the members 62 with the base element 26, this movement will pull the bent portions B in base element 24 back into alignment. Also, any of the cross-braces 28 connected to base element 24 which may have buckled upon the deformation of the portion B will also be straightened, somewhat, even though it may be necessary to apply additional straightening forces with a mallet, or the like (not shown).

Once base element 24 has been straightened, the clamp members 62 engaging unbent portions of base element 26 are released. The ram 54 is advanced until shoulder 55 engages base element 24 along substantially the entire length thereof, whereupon additional clamping members 64 are employed to firmly clamp base element 24 to ram 54. Next, ram 54 is again retracted so that the inwardly bent portions B in base element 26 are pulled into alignment. Obviously, whether base element 24 or base element 26 is straightened first, is a matter of choice, such that the above-mentioned sequence may be reversed, if desired.

The second procedure and the type of accessory adapted for use in the straightening of inwardly bent portions B are shown schematically in FIGS. 9 and 10. In this regard, an extension assembly or assemblies 70 are employed in conjunction with the shoulder 50 and a ram 54 such that movement of said ram 54 toward the shoulder 50 produces the straightening forces obtainable with this particular arrangement of the first die means 38. Each extension assembly is comprised of a clamp 72 mounted directly to shoulder 50, a rod portion 74 and a plate member 76 carried by said rod and engage-d with portion 6B7.

Considering first FIG. 9, which illustrates the straightening of base element 24, a tower section 20 is placed on bed 36 such that base element 26 is spaced slightly from shoulder 50 along the entire length thereof. One or more extension assemblies 70 are then mounted to shoulder 50, such that they engage an inwardly bent portion B in the opposed base element 24, as illustrated. Once this condition is reached, movement of ram 54 in the direction indicated by arrow 80 will tend to move the entire tower section 20 toward shoulder 50; however, due to extension assemblies 70, the bent portions B in element 24 will be forced outwardly of the tower section 20, back into alignment with the remaining, unbent segments of said element 24.

In FIG. 10, the procedure for straightening base element 26 is shown. In this instance, the tower section 20 is positioned such that base element 26 is engaged initially with shoulder 50, with shoulder 55 spaced from base element 24. Next, an extension assembly 70 is mounted. to the ram 54 opposite to and in engagement with each inwardly bent portion B in base element 26. The ram 54 is now advanced, and due to its spacing from the tower section 20, said section is engaged only by the extension plate 76 of each assembly 70, such that movement of the ram 54 is continued until said bent portions B are forced into engagement with the shoulder 50 to complete the straightening of element 24.

As was the case with the first type or embodiment of straightening accessories discussed, the procedure of FIGS. 9 and 10 will also tend to straighten any crossbraces 28 which may have buckled in the area of the bends B. It should be kept in mind, however, that these cross-braces 28 may have to be struck with a hammer in order to complete the straightening procedure since they are not engaged directly by the die means 38. However, the forcing of the bent portions B back into alignment will set up tensile stresses in any of the buckled crossbraces 28 tending to straighten them, such that when struck they will virtually pop back into alignment.

In FIGS. 4 and 6, the construction and mode of opera tion of the second die means 40 used. to straighten the apex element 22 are illustrated. While this particular straightenin operation is being discussed subsequent to that used for base elements 24 and 26, the particular sequence employed is not critical and the various operations may be reversed, repeated or employed in any manner necessary to attain the degree of straightening desired.

Basically, second die means 40 are comprised of an upper die assembly 82 and a lower die assembly 84. The upper assembly 82 includes an elongate, substantially flat carriage member 86 which is mounted at its opposite ends on two pairs of standards 88. These standards 88 are threaded as indicated at in FIG. 4, and are engaged with brackets 92 carried by said carriage 82. The brackets 92 are also threaded so that rotation of the standards 88 may be employed to produce vertical movement of carriage 86. As best seen in FIG. 2, each standard 88 is ro tatably mounted to the frame 34 by brackets 94, and each has a bevel gear 96 on the lower end thereof. The respective bevel gears 96 are matingly engaged with corresponding bevel gears 98 carried on a shaft 100 which is rotatably mounted to the legs 34 and includes a hand crank 102 for producing the above-mentioned vertical movement. This manner of drive for carriage 86 is presented solely by way of illustration, and intended that movements of carriage 86 may be effected by means other than that shown.

The undersurface of the carriage 86, that facing the bed 36, is provided with an elongate forming channel 104 adapted to receive the outer surface of the apex element 22 therein. The walls of the channel 104 are disposed such that they correspond in shape to the exterior of the apex element 22, which in the illustrated embodiment approximates a right angle.

In addition, carriage 86 includes a plurality of downwardly extending spar or column-like elements 87. These column-like elements 87 are designed to be engaged with a series of clamping bars 89 to maintain the base elements 2 4 and 26 in position on the bed .36 during straightening of the apex element 22. The clamping bars 97 are disposed in engagement with the upper surfaces of the shoulder 50 and the ram 54 such that they extend through the tower section and either engage or are closely spaced from base elements 24 and 26. The spar-like members 87 are sized such that when carriage 86 is lowered into engagement with the apex element 22, said members 87 firmly engage bars 89 forcing them against the shoulder 50 and ram 54. When this relationship is achieved, as shown in FIG. 6, the base elements 24 and 26 are clamped in position on the bed portion 36 such that their movement away from said bed portion is restrained. The specific purpose for this clamping of the base frame elements 24 and 26 will be apparent from the description of the straightening operation performed by the second die means 40 to be set forth hereinafter.

The construction of the lower die assembly 84 is best viewed in FIG. 6. As can be seen, the bed 36 includes a plurality of apertures 106 which are formed in an upper plate member 36 that functions to define a segment of said bed 36. The apertured plate 36 is part of a structural assembly designated generally 110 which includes, in addition to said plate .36, a pair of parallel wall elements 112 and 114 and a lower plate member 116. The apertures 106 open downwardly into an elongate chamber 118 defined between the spaced parallel wall members 112 and 114. Disposed in the chamber 118 in alignment with the respective apertures 106 are a plurality of double-acting piston arrangements 120, each of which has a die element 122 carried by its piston rod 121. Accordingly, die element 122 may be extended upwardly from the bed 36 into engagement with the interior surface of apex element 22. The die element 122 of the illustrated embodiment is in the form of a short section of angle-iron that conforms to the shape of the inner surface of the apex element 22.

Accordingly, to effect straightening with the upper and lower die assemblies of the second die means 40, the clamping bars 89 are first positioned as shown in FIG. 4,

and the carriage 86 is lowered to cause the spar-like members 87 to engage said clamping bars 89, and to dispose the apex element 22 in channel 104. Once this has been accomplished, operating fluid is supplied to the doubleacting pistons to extend the die elements 122 upwardly from bed portion 36 into forcible engagement with the interior surface of the apex element 22.

With the above-discussed arrangement, the channel 104 functions as the forming groove into which any bends in the apex element 22 are forced by the various die elements 122 which, in effect, function collectively as a mandrel. The end result being that any deformations, irregularities or bends in the element 22 are straightened. Also, any of the cross-braces 28 which interconnect apex element 22 with the base elements 24 and 26, will be placed in tension by the operation, due to the fact that the base elements 24 and 26 are maintained in position on the bed portion 36. Therefore, any of these cross-braces 28 which may have buckled during distortion of the frame elements, will have a straightening force applied thereto. In many instances, this force will be sufiicient to cause the crossbraces 28 to straighten out; however, due to the fact that the brace is in tension, it need only be struck with a hammer so that the force of the blow or blows, coupled with the tensile stress previously established, are all that are needed to quickly straighten these elements.

Considering briefly the above-discussed function of the lower die assembly 84, it should be noted that when a tower section 20 is in position on bed 36, certain of the cross-braces 28 which interconnect base elements 24 and 26 may overlie the apertures 106 so as to interfere with the operation of die elements 122. Also, it is evident that the apex element 22 will most probably be bent or distorted at only several locations along its length, obviating the need for engagement thereof by die 122 along its entire length. Accordingly, with the above-noted factor in mind, the means (not shown) provided for operating the respective double-acting pistons '120 will include valving arrangements of known construction which enable an operator to employ selectively individual die elements 122 such that only the accessible bent portions of the apex element 22 are engaged thereby.

Keeping in mind the fact that the above-discussed straightening procedures may be performed in any desired sequence, the operation of the apparatus of the present invention will now be described concerning the straightening of a typical tower section 20. First the tower section 20 is placed on the bed 36 and the ram 54 and shoulder 50 of the first die means 38 are employed to straighten any outwardly bent portions A in base elements 24 and 26. Next, the various accessories, as discussed regarding FIGS. 3, 5 and 7, and FIGS. 9 and 10, are employed to straighten any inwardly bent portions B in said base elements 24 and 26. In this regard, the various straightening procedures may, if desired, be performed while the respective base elements are placed in tension by the application of an axial load to the entire tower section 20 effected with the reciprocal member 42, as discussed with regard to FIGS. 2 and 5. The application of tensile stresses to the frame members complements the straightening forces applied by the die means 38 thereby providing for improved results.

Once the frame elements 24 and 26 have been straightened, ram 54 is moved into position and clamping bars 87 are inserted so as to rest upon shoulder 50 and said ram. The carriage 86 of the upper die assembly 82 is lowered to clamp the base elements 24 and 26 in position on bed 36 and to engage the apex element 22 in forming channel 104. Next, the lower die assembly 84 is employed to engage the interior surface of the apex member 22 to apply straightening forces thereto which, as discussed previously, are adapted to establish tensile stresses in any of the bent cross-braces connected to the apex element in the area of the deformations therein. Should the cross-braces 28 not immediately straighten or pop back into position, they need only be struck with a hammer to attain this action. The operation of the lower die assembly 84 is such that since certain of the cross-braces 28 may overlie apertures 106, thus interfering with the operation of the underlying piston arrangement 120, operating fluid is supplied to only selected ones of said pistons 120, and then generally only to those immediately underlying bends in said apex element 22.

As was the case with the straightening procedure employed with the first die means 38 during the application of straightening forces by the upper and lower die assemblies 82 and 84 of the second die means 40, the tower section may have an axial load applied to it by the reciprocal member 42 suflicient to place the frame elements 22, 24 and 26 in tension. While this use of an axial load, combined with the application of straightening forces, greatly enhances the quality and speed of the entire straightening operation, it should be noted that this procedure may or may not be employed as desired.

In addition, should the apex element 22 be deformed or bent at locations that are inaccessible with the die element 122 of the second die means 40 due to the interference of the cross-braces 28 mentioned previously, die means 38 may be employed to effect straightening. In this regard, the tower section 20 is rotated so that the apex element 22 rests on bed 36, thus enabling these previously inaccessible bends in element 22 to be straightened in the same manner as discussed with regard to frame elements 24 and 26.

As a possible alternate to this procedure for straightening inaccessible bends in apex element 22, the die elements 122 could be removably mounted on the piston rods 121 so that these could be raised above the level of the cross-braces 28 and then the die elements 122 attached, or for that matter, a single elongate die element employed. With this arrangement, the instances of interference of cross-braces 28 with the lower die assembly 84 would be reduced considerably.

Accordingly, the apparatus and method described above provides for the straightening of scaffolding tower sections in a manner so as to now make refurbishing of these sections an economically feasible procedure. Also, it should be understood that the embodiments or variations of the present invention disclosed in the drawings and specifically discussed above, are but preferred arrangements, and it is envisioned that those skilled in the art may make various substitutions, changes or alterations therein, without departing from the spirit and scope of this invention, which is defined solely by the claims appended hereto.

We claim:

1. Apparatus for straightening elongate tower sections, or the like, of the type having a generally triangular configuration in section and comprised of a pair of base frame members and an apex frame member, said members being joined each to the other by a plurality of crossbraces, wherein said frame members and said crossbraces have become bent or otherwise distorted during use, said apparatus comprising: a frame having a bed portion upon which said pair of base frame members are adapted to rest in supported engagement; first die means including an elongate shoulder disposed adjacent an edge of said bed portion, and elongate ram means operably disposed relative to said bed portion on a side opposite said first shoulder means and thereby defining a second shoulder means, said ram means being reciprocal to provide for relative movement between said first and second shoulder means which movement may be employed in establishing straightening forces in said base frame members and the interconnecting cross-braces; and second die means for engaging said apex frame member, to establish straightening forces in said apex frame member and the cross-braces joining said member to the base frame members.

2. Apparatus as defined in claim 1, further including means for applying an axial load to said tower section in order to place the respective frame members in tension during the application of straightening forces thereto.

3. Apparatus as defined in claim 2 wherein said means for placing an axial load on the tower section include means for fixedly positioning one end of said tower section, and a reciprocal member connectible to the other end of said tower section and movable away from said fixed end for applying said axial load.

4. Apparatus as defined in claim 2 wherein said means for placing an axial load on the tower includes a die member disposable in axial alignment with the tower section and adapted to be received within an end thereof to straighten any bends in the adjacent portions of the frame members; means for attaching said die member to said tower section after disposal within said end, and means operably connected with said die element for effecting reciprocal movement such that a tensile load may be applied to said section.

5. Apparatus as defined in claim 1 wherein said second die means include relatively movable upper and lower die arrangements.

6. Apparatus as defined in claim 5 wherein said upper die arrangement includes a vertically movable member having means defining an elongate channel which conforms substantially to the configuration of the outer surface of said apex frame member and is adapted to receive same therein, such that upon engagement of said apex frame member by said lower die arrangement, said apex member will be forced into said channel thereby straightening any bends or irregularities therein.

7. Apparatus as defined in claim 6 wherein said lower die arrangement includes a plurality of recesses formed in said bed portion, a die element disposed in each said recess and having a surface thereon conforming in shape to that of the inner surface of said apex frame member, and means for effecting reciprocal movement of said die elements to bring them into engagement with the interior surface of said apex frame member thereby to effect said forcible position of the outer surface of said member in said channel of the upper die arrangement.

8. Apparatus as defined in claim 7 wherein said means for effecting reciprocal movement of said die elements include a plurality of double-acting fluid operated piston assemblies, and means for controlling the supply of operating fluid to said piston assemblies.

9. Apparatus as defined in claim 8 wherein a piston assembly is provided for each said die element, and said means for controlling the supply of operating fluid include means providing for the individual operation of said piston assemblies whereby only selected ones of said die elements may be used to engage the apex frame member.

10. Apparatus as defined in claim 1 further including means for restricting movement of said pair of base frame members away from said bed portion upon the application of straightening forces to said apex frame member, such that a tensile stress may be applied to at least certain ones of said cross-braces which interconnect the base frame members to said apex frame member.

11. Apparatus as defined in claim 10 wherein said means for restraining movement include a plurality of clamping bars adapted to overlie and engage said base frame members, and a plurality of spar-like members carried by and movable with said second die means, said spar-like members being sized to engage said clamping bars when said second die means is in the operating position which engagement maintains the position of said clamping bars and correspondingly said base frame members upon the application of straightening forces to said apex frame member.

12. Apparatus for straightening elongate tower sections, or the like, of the type having a generally triangular configuration in section and comprised of a pair of base frame members and an apex member, said members being joined each to the other by a plurality of cross-braces, wherein said frame members and said cross-braces have become bent or otherwise distorted during use, said apparatus comprising: a frame having a generally horizontally disposed bed portion upon which the base frame members of a tower section are adapted to rest in supported engagement; first die means operably disposed relative to said bed portion for applying straightening forces to said base frame members; and second die means disposed generally transverse to said bed portion and said first die means for applying straightening forces to said apex frame member.

13. Apparatus as defined in claim 12 further including means for restraining movement of said pair of base frame members away from said bed portion during the application of straightening forces to said apex frame member, such that said application is effective to establish tensile stresses in the cross-braces joining the apex frame member to said base frame members.

14. Apparatus as defined in claim 12 wherein said first die means include an elongate shoulder disposed along one edge of said tower section supporting bed portion, and elongate reciprocal ram means disposed along the opposite edge of said bed portion defining second shoulder means, relative movement between said shoulder means providing for the application of straightening forces to one or the other of said base frame members.

15. Apparatus as defined in claim 14 wherein said first die means further include first clamping means adapted to be carried by said first shoulder means for engagement with the base frame member disposed adjacent thereto, and second clamping means carried by said reciprocal ram means for engagement with the other of said base frame members, such that movement of said ram means in a direction away from said first shoulder means may be employed to apply straightening forces to said base frame members.

16. Apparatus as defined in claim 15 wherein both said first and second clamping means include a plurality of clamping members, said members being positionable at various locations along the length of said shoulder and said ram means, respectively, such that said straightening forces may be applied at selected locations along the length of the tower section.

17. Apparatus as defined in claim 14 wherein said first die means include one or more extension arrangements adapted to be clamped to either said first or said second means, so that said extension arrangement may be employed to engage a bend or irregularity in the base frame member disposed remote from its point of attachment, whereby movement of said ram means in a direction toward said first shoulder means may be employed to apply straightening forces to bends in said base members which extend generally inwardly of the tower section.

18. Apparatus as defined in claim 17 wherein said extension arrangements include, a clamp element for engagement with either said first or said second shoulder means, a rod portion integrally connected with said clamp element at one end thereof, and a plate member carried by the other end of said rod portion and adapted for engagement with said frame members.

19. Apparatus as defined in claim 12 further including means for selectively applying an axial load to said tower section such that the application of said straightening forces to said frame members may take place when said frame members are stressed in tension.

20. A method of refurbishing elongate tower sections by means of a straightening press, said sections being of a type having a generally triangular configuration in section and comprised of a pair of elongate base frame elements and an eiongate apex frame element, with said elements being interconnected each to the other by a plurality of cross-braces, said method comprising the steps of: disposing a tower section on a bed portion of a straightening press with the base frame elements in engagement therewith; applying straightening forces to said base frame elements at selected locations by use of a first die means of said press; and applying straightening forces to said apex frame member by use of a second die means of said press.

21. A method as defined in claim 20 wherein said step of applying straightening forces to said apex frame member includes the step of restricting movement of said base frame members away from said bed portion so that tensile stresses will be established in those cross-braces joining the apex frame element to said base frame elements.

22. A method as defined in claim 20 further including the step of applying an axial load to said tower section to place said frame elements in tension during the application of straightening forces.

23. A method as defined in claim 22 wherein said step of applying an axial load to said tower section includes the steps of fixedly positioning one end of said section relative to the base portion of the press, attaching the other end of said tower section to a reciprocal member of said press disposed in axial alignment with said section, and retracting said reciprocal member axially of said tower section in a direction away from said one end.

24. A method as defined in claim 20 wherein said first die means of the press include a pair of elongate generally parallel relatively movable shoulder means, and said step of applying straightening forces to said base frame elements further includes: engaging said base frame elements with said shoulder means by movement thereof toward each other such that bends or irregularities in said base frame elements extending outwardly of the tower section in the plane of said elements will be engaged by said shoulder means prior to the engagement of the remaining unbent portions of the frame elements, and continuing relative movement of said shoulder means to force said outwardly bent portions into alignment with said unbent portions of said element.

25. A method as defined in claim 24 wherein said step of applying straightening forces to said base frame elements further includes the steps of: providing clamping means mountable on said relatively movable shoulder means and engageable with said base elements; engaging said base elements at selected locations wherein said elements are bent inwardly of the tower section with said clamp means; effecting relative separating movement between said shoulder means such that the inwardly bent portions are forcibly moved into alignment with the remaining unbent portion of said elements.

26 A method as defined in claim 24 wherein said first die means of said press include one or more extension members adapted to be carried by either said shoulder means and to engage inwardly bent portions of the base element disposed adjacent the opposite shoulder means, and said step of applying straightening forces to said base frame element includes the steps of attaching an extension element to one or the other of said shoulder means at a location such that said extension element engages an inwardly bent portion of the base element disposed adjacent the other said shoulder means; and effecting relative movement of said shoulder means toward each other such that said extension members apply an outwardly directed force to said inwardly bent portions to straighten same.

27. A method as defined in claim 20 wherein said first die means of said press include a pair of elongate relatively movable first and second shoulder means and one or more extension members adapted to be carried by either shoulder means and to engage inwardly bent portions of a base element disposed adjacent the opposite shoulder means; and said step of applying straightening forces to said base frame element includes the steps of: attaching an extension element to one or the other of said shoulder means at a location such that said extension element engages an inwardly bent portion of the base element disposed adjacent the other said shoulder means; and effecting relative movement of said shoulder means toward 13 each other such that said extension members apply an outwardly directed force to said inwardly bent portions to straighten same.

28. A method as defined in claim 20 wherein said first die means of the press include a pair of elongate generally parallel relatively movable shoulder means, and said step of applying straightening forces to said base frame elements includes the steps of: providing clamping means mountable on said relatively movable shoulder means and engageable with said base elements; engaging said base elements at selected locations wherein said elements are bent inwardly of the tower section with said clamp means; effecting relative separating movement between said shoulder means such that the inwardly bent portions are forcibly moved into alignment with the remaining unbent portion of said frame elements.

29. A method as defined in claim 20 wherein said die means of the press include upper and lower relatively movable die assemblies, wherein said upper assembly includes a forming channel, and said step of applying straightening forces to the apex element includes the steps of: positioning the upper die assemblies in engagement with the outer surface of said apex frame element; engaging the inner surface of said apex element with the lower die assembly to forcibly dispose said apex element in said forming channel.

30. A method as defined in claim 29 wherein said step of engaging the inner surface of the apex frame member includes the step of: controlling the operation of said lower die assembly so as to engage said apex frame element at only selected locations.

31. A method of refurbishing a bent scaffolding section of the type having a generally triangular configuration in section and comprised of a pair of base frame elements and an apex frame element with each said element being interconnected with the others by a plurality of crossbraces, said method comprising the steps of: applying an axial stress to said tower section to place said frame elements in tension; and applying straightening forces to the bent portions of the individual frame elements while maintaining said axial stress on the tower section such that a corresponding tensile load is established in said cross-braces tending to straighten same without the direct application of forces thereto.

32. A method as defined in claim 3-1 wherein said step Of applying straightening forces to the frame elements in- 14 eludes the step of: restraining movement of the base frame elements in a direction toward said apex frame element during the application of straightening forces to said apex frame element.

33. Apparatus for refurbishing a bent elongate tower section, or the like, of the general type having a triangular configuration in section and comprised of a pair of base frame members, and an apex frame member, said members being joined each to the other by a plurality of cross-braces, said apparatus being adapted for the straightening of said sections, and comprising: a frame having a bed portion upon which the base frame members of a tower section are adapted to rest in supported engagement; first shoulder means extending along the length of a first edge of said bed and adapted to engage one of said base frame members, and second shoulder means operably positioned relative to said bed portion for engaging the other of said base frame members and being defined by elongate reciprocal ram means to provide for relative movement between said shoulder means, such that said shoulder means may be employed to establish straightening forces for said base frame members and the cross-braces interconnecting said members; and relatively movable upper and lower die means for engaging said apex frame member to apply thereto, and to the cross-braces joining said apex member to the base frame members, straightening forces.

References Cited UNITED STATES PATENTS 846,463 3/1907 Gardner 72453 1,659,181 2/1928 Woods 72-389 1,907,925 5/1933 Wochner 72389 3,034,563 5/1962 Gaspar 72-389 FOREIGN PATENTS 182,285 6/1955 Austria 72-412 535,304 4/1941 Great Britain 72412 CHARLES W. LANHAM, Primary Examiner G. P. CROSBY, Assistant Examiner Us. 01. X.R. 72 339, 412, 453, 705 

